Self-locking tackle-block.



No. 756,747. PATENTED APR. 5, 1904. J. 0. WALTON.

SELF LOCKING TACKLE BLOCK.

APPLICATION FILED we. 12. 1903.

N0 MODEL.

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rm: nouns PEYERS an. PNDYO-LIINO.. WA$HING1ON n cramping-pulley a secondplain pulley was ar- To all whom, it 71mg concern:

groove in a plane at right angles to the axis and block without a loadon it the rope is at times Patented April 5, 1904.

PATENT OFFICE.

JOSEPH O. WALTON, OF BOSTON, MASSACHUSETTS.

SELF-LOCKING TACKLE-BLOCK.

SPECIFICATION forming part of Letters Patent No. 756,747, dated April 5,1904.

Application filed August 12, 1903.

Be it known that I, J OSEPH O. WALTON, a citizen of the United States,residing at Boston, in the county of Suffolk and State of Massachusetts,have invented a new and useful Improvement in Self-LockingTackle-Blocks, of which the following is a specification.

In the patent granted me February 19, 1901, No. 668, 594:, I have shownand described a selflocking pulley-block in which the lockingpulley orsheave was formed with a concentric with a lateral extension bearing oneor more cam-grooves leading off to one side into a different plane andinto which the rope was led by a lateral adjustment of its free end, soas to cause the rope to be pinched and held between the cam-groove and apinching-roller above, which latter had a stop projection on it thatallowed the roller to first rotate under the initial pinching strain ofthe rope to avoid a scraping strain on the rope and then through thestop acting upon a stationary part of the block brought the roller to astandstill, so as to positively lock the rope with a firm hold. Inconnection with this form of sheave or ranged beside it within the sameframe and upon the same axis, but arranged to rotate independently ofthe cramping-pulley to ac commodate the differential speed of the ropeas it passes from one sheave to the opposite block and back again to thecramping-pulley. This form of block works well; but upon manipulating oroverhauling the rope in the liable to catch on the locking part of theblock, which causes considerable trouble and loss of time in getting itout.

My present invention consists in a simple guard combined with or formedon the block on its rear side just behind the cramping-pulley, so thatthe run of this part of the rope will be thrown laterally away from thecramping-face on the rear side, but will not interfere with the lockingof the rope on the front side, as will be hereinafter described withreference to the drawings, in which Figure 1 is a front view of mypatented Serial No- 169,232. (No model.)

tackle-block with the run of the rope connecting it to a plain doubleblock below. Fig. 2 is a rear view of the same tackle-block, showing myguard applied to the same; and Fig. 3 shows one of my tackle-blockswithamodified form of guard.

In the drawings, A represents the frame of my tackle-block, which may bemade of wood, metal, or any other suitable material. It has two cells orcompartments a and a, in which upon the same axial pin P are mounted thetwo independently-rotating sheaves or pulleys B and B B. B is a plainconcentrically-grooved sheave, while the other is wider and has aconcentric grooved face B and one or more eccentric cam-grooves Bleading out from the groove B laterally into a different plane. Thesegrooves B diminish in depth as they proceed laterally from groove Buntil they run out or gradually taper into the outer periphery of thesheave, so as to form cramping-faces to compress the rope between themand a superposed roller or rolling-pin O. This roller is preferably setat an incline, as shown, and has a stop projection 0, which after thebacklash of the rope has given an initial turn to the roller or pin Ccomes into stopping contact with the frame of the block and locks saidpin or roller against further turning, so that it now positively locksthe rope, all as set forth in my previous patent referred to.

The run of the rope in hoisting is indicated by the arrows. It passesdown at 1 from my block A to the lower block D and around its sheave cl.Rising on the rear side, (see Fig. 2,) it passes up at 2 to sheave B ofmy block. Thence passing down at 3 in front it turns around the sheave dof the lower block D,

and then rising at 4: in the rear it enters thecramping-pulley of myblock and passing over it to the front terminates in the free end 5,which is in the hand of the person manipulating it. By throwing the end5 of the rope so long as there is a considerable weight on the hook E;but it sometimes happens that the lower block D is to be raised orlowered without a weight on it, as when barrels, boxes, &c., are beingraised to or lowered from the upper story of a warehouse. In such casewhen the lower block D is to be readjusted the run 4 of the rope isliable to get caught or reengage the cramping-face and remain lockedbetween it and the pin above. To prevent this, I have provided on therear side of my tackle-block an inclined guard G, whose edge 00 occupiesan angle that makes the cellopening wider at the top than it is at thebottom. This causes the run 4 of the rope which is behind the pulleyfrom the operator to have a trend always in the direction of arrow 3toward the concentric free-running groove B and effectually prevents allaccidental locking. The importance of this will be understood when itisremembered that the operator has no control over any lateral movement ofthe run 4 of the rope, since it is behind both blocks, and the stiffnessof the rope and the influence of the weight raised is liable to leavethe upper end of section 4 of the rope with a set or bend in it thatprevents it from returning to the free-running groove B unless aided bythe guard G. This guard effectually removes the difliculty and rendersthe block perfectly efficient and reliable in operation whether loadedor not.

In wooden blocks the guard G is conveniently formed in a separate metalplate or bar G, having a flanged and inclined edge on; but in smallblocks in which the frame is of metal it is to be cast with the frame,as seen at G in Fig. 3. It is obvious that this same construction may beemployed in larger blocks of any size.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. A self-locking tackle-block comprising a frame, a cramping-pulleycomposed of a concentrically-grooved portion and aneccentrically-grooved cam portion extended laterally therefrom, and aguard arranged on the rear side of the block to throw the rope towardthe free running groove substantially as described.

2. A self-locking tackle-block comprising a frame, a cramping-pulley,and a guard arranged on the rear side to throw the rope into releasedposition substantially as described.

3. In a self-locking tackle-block, a frame having a cell to receive thecramping-pulley, said cell having a larger opening on the rear side atthe top than it has at the bottom.

4. In a self-locking tackle-block, a frame having a cell to receive thecramping-pulley said cell having on its rear side an inclined guardsubstantially as described.

JOSEPH O. WALTON. r

Witnesses:

EDW. W. BYRN,

SoLoN C. KEMON.

